1. Field of the Invention
In general, the present invention relates to a golf club and especially the shaft thereof. More especially, the present invention relates to a golf club shaft which is twisted to correct the direction of the front face of a club head installed on the front end thereof such that the front face of the head club is substantially coincident with the direction in which the golf ball should fly and to a golf club comprising the golf club shaft. Thus, a player can swing the golf club without being conscious of the correction of the player's swinging form.
2. Description of the Related Art
The orbits of golf clubs are different according to players because the player's swinging forms are different from one another. It is not easy to fly the golf ball in the aimed direction: In hitting a golf ball without being conscious of correcting the player's swinging form, even though the player thinks that the player has hit the ball by directing the front face of the head to the direction in which the golf bail should fly, at the time of impact of the golf ball on the head, thc front face of the head is liable to be directed to directions different from the direction in which the ball should fly. This tendency is found outstandingly in beginners who have not had much experience in playing golf and have not corrected their swinging forms appropriately: Normally, at the time of the impact of the golf ball on the club head, the front face of the club head deviates in the almost same direction from the direction in which the golf ball should fly.
Although a slicer thinks that the slicer has hit a golf ball (B) by directing the front face of the club head to the direction in which the golf ball (B) should fly, the arrival time of a toe side 112A of a club head at the golf ball (B) is liable to lag behind the arrival time of a heel side 112B thereof at the golf ball (B), as shown in FIG. 39A. Thus, many of the golf balls (B) hit by the slicer slice, as the name implies. For example, in the case of a right-handed player, many golf balls (B) slice to the right, whereas in the case of a left-handed player, many golf balls (B) slice to the left. Similarly, although a hooker thinks that the hooker has hit the golf ball (B) by directing the front face of the club head to the direction in which the golf ball (B) should fly, the toe side 112A of the club head is liable to arrive at the golf ball (B) earlier than the heel side 112B, as shown in FIG. 39B. Thus, many of the golf balls (B) hit by the hooker hook, as the name implies. For example, in the case of a right-handed player, many golf balls (B) hook to the right, whereas in the case of a left-handed player, many golf balls (B) hook to the left.
When a player who swings the golf club comparatively appropriately uses an iron club, in some cases, the direction of the front face of the head deviates from the direction in which the golf ball should fly at the time of impact of the club head on the golf ball as in the case of the slicer or the hooker. That is, because the shaft of the iron club of the low-number side is longer than that of the iron club of the high-number side, it is difficult for the player to swing the club or the low-number side appropriately. Further, the loft (loft angle) of the shaft of the iron club of the low-number side is smaller than that of the shaft of the iron club of the high-number side. Thus, the player cannot give the golf ball a spin and cannot fly the golf ball high unless the player swings the iron club of the low-number side with a considerable great force. As such, many golfers have the problem that they cannot fly the golf ball longer than they expect when they hit it with the iron club of the low-number side. Thus, to fly the ball long, they apply a greater force than is required to the upper part of their bodies. As a result, their bodies turn forward much faster than their wrists. Consequently, right-handed golfers often fly the golf ball toward the right with respect to the target point. Likewise, left-handed golfers often fly the golf ball toward the left with respect to the target point. On the other hand, because the shaft of the golf club of the high-number side is shorter than that of the club of the low-number side, the golfer's hands pass close to the body when they swing it and the golfers are liable to turn their wrists forward faster than their bodies. Consequently, right-handed golfers often fly the golf ball toward the left with respect to the target point. Likewise, left-handed golfers often fly the golf ball toward the right with respect to the target point. That is, the golfers are liable to hook the golf ball. The tendency is found even in many middle-grade or high-grade golfers.
Needless to say, in order for the golfer to improve the score, it is necessary to hit the golf ball straight in the direction the golfer has aimed. Therefore, it is necessary for the slicer and the hooker to correct their swinging forms. But it is very difficult for them to correct their swinging forms.
A misshot which occurs in using the iron club is caused by the fact that the orientation of the front face of the club head in addressing the golf ball is not coincident with that of the front face of the club head in hitting it. This is because the lengths of the shafts of the iron clubs constituting a set of iron clubs are different from one another, depending on the numbers of the iron clubs, as described above. However, it is not easy to increase the swinging speed in hitting the ball with the club of the low-number side without applying a greater force than is required to the upper part of the golfer's body. Further, it is not easy to appropriately change the golfer's swinging form when the golfer swings the club of the low-number side and the club of the high-number side in consciousness of the variation between the orbit of the club of the low-number side and that of the club of the high-number side. That is, not only the slicer or the hooker, but also many middle-grade or high-grade golfers who swing the club comparatively appropriately have the problem of misshots which occur when they use the iron club.